The author proposes an abstract form for the base categorial component of a transformational grammar--a form which represents categories and relations (functions) in a way that holds reasonable promise for resolving certain very broad problems of the interplay between linguistic form and function. The problems are so broad that almost everything in syntax is relevant to them. The phenomena selected by the author to illustrate the problems and indicate the reasons for proposing a particular solution are: (1) prepositions and functions, (2) case relations, (3) relations and category labels, (4) relations and configurations, (5) relations of heads and complements, (6) cases and features, (7) case and the embedding of sentences, (8) case features and categories, and (9) form and function. (DO)